Striking and damping mechanism for pianos



April 4, 1950 H. G. LINDEROTH STRIKING AND DAVIPING MECHANISM FOR PIANOSFiled June 12, 1946 Fig- I N VEN TOR. HAM: Com/AK .L/mmam A TTORNEYPatented Apr. 4, 1950 UNITED STATES PATENT OFFICE STRIKING AND DAMPINGMECHANISM FOR PIANOS 11 Claims. 1

This invention relates to piano actions and particularly to the strikingand damping mechanisms thereof.

Piano actions as heretofore constructed have involved complicatedmechanism controlling the operation of the hammers and dampers from thekeyboard, this mechanism being difiicult and expensive to make andinstall. The object of this invention is to provide a novel controlmechanism which requires fewer parts, is relatively easy and inexpensiveto construct and assemble, has an eilicient, positive action andrequires relatively few adjustments of interrelated parts.

In the accompanying drawing, which illustrates a preferred form ofstriking and damping mechanism of the invention:

Fig. 1 is a view partly in vertical section, partly in side elevation,of the mechanism embodied in an upright type piano, showing in dottedlines an actuated position of certain parts;

Fig. 2 is detail elevation view of part of the mechanism shown in Fig.1.

Referring to Fig. 1 of the drawing, the mechanism as shown comprises asupport rail l extending the full length of the piano between thekeyboard keys l2 and the strings l4. Rail I0 is provided along its upperedge adjacent the keyboard with a longitudinal groove l6 and in its endsurface adjacent the strings with a second longitudinal groove IS, thegrooves i6 and I8 extending the full length of the rail between thekeyboard and the strings. Grooves I6 and 8 are, as shown, provided withundercut ends curved away from the center line of the groove and forminga restricted entrance throat or slot for the groove in the face of therail.

The dampers 2d are each provided with the usual damper tip 22 and with abase 24 within which is anchored one end of a curved spring clip 26.Clip 26 is provided with a curvature generally conforming to that ofgroove [8 but of somewhat larger diameter and is adapted to becontracted by pressing its free end toward its anchored end forinsertion through the restricted throat of groove it, the clip thenexpanding to fit tightly against the walls of the groove with the freeand anchored ends protruding through the throat as shown in the drawing.The clip is formed of a flat, resilient strip providing a substantialbearing surface frictionally engaging the walls of the groove. Further,the clip is so formed and connected to the base of the damper that, whenseated in groove iii, it resiliently supports and urges the damper toits normal position shown in full lines in Fig. 1 in which the damperbase 24 is supported outwardly and free of rail ID on the end of clip26, with the damper shaft inclined rearwardly and its tip 22 in dampingengagement with the corresponding string I 4.

The hammer 23 is provided with the usual striking tip 30 and with a base32 in which is anchored one end of a spring clip 34 similar to the clip26 and like the latter adapted to be seated under pressure within thecorresponding groove 16, with the anchored and free ends protruding fromthe groove to support the hammer base above and. free of rail in. Clip34 is so constructed that when seated in groove l6, its protruding endattached to the hammer resiliently urges the hammer to a normal positionshown in full lines in Fig. 1 in which the hammer shaft is inclinedforwardly toward the keyboard and its tip 30 is away from thecorresponding string l4.

An actuating cord 36 of nylon or the like, Spun, braided or plain, isafiixed at one end to damper 20 near its base 24, extends forwardlythrough a slot 38 in clip 34 below hammer base 32 and upwardly about thecurved forward side of said base to the corresponding key 12 where itsopposite end is wound on a take-up spindle 4U rotatably mounted onthe'inner end of the key, the string extending downwardly through a slot42 in the key. The base 32 of hammer 30 is provided, on the side engagedby cord 36 with projecting ribs 44 (Fig. 2) forming between them a trackfor the cord, these ribs maintaining the cord in constant engagementwith the curved side of the base.

When key i2 is depressed about its pivot, the lifting of its inner endexerts a longitudinal pull on cord 36, causing damper 20 to rockforwardly on spring clip 26, the end of the clip attached to the damperflexing beneath the forward shoulder 46 formed by the restricted throatof groove l8. The damper is thus brought to its dotted line position ofFig. 1 in which its base 24 is cushioned against a felt 48 secured tothe contiguous rear edge of rail l0 above groove I8 and the tip 22 iswithdrawn from the string I4. Cord 36 is also tensioned against thecurved surface of base 32 of hammer 28 between ribs 44 exerting arearward pressure on the base which causes the hammer to rock rearwardlyon spring clip 34, the clip flexing beneath the rear shoulder 59 formedby the restricted throat of groove l6.

This brings hammer 28 to the dotted line position of Fig. 1 in which itsshaft is inclined rearwardly and its tip 30 is close to the string l4.

From this position the rearward momentum of the hammer carries itfurther rearwardly so that the tip strikes the string M which stops therearward motion of the hammer and permits the hammer to reboundimmediately, under the pressure of spring 34, to its dotted lineposition away from the string, in which position it is stopped by thetension of cord 36 and is held thereby against the pressure of thespring until the pressure on key 12 is released permitting the parts toreturn to their full line normal positions with the damper engaging anddamping the string. To insure that the damper is fully released from thestring l4 before the string is struck by the hammer, its spring 26 ismade somewhat weaker than hammer spring 34 so that the tensioning ofcord 36 preferentially flexes spring .28 moving the damper to itsrearward position before completely actuating hammer 28.

My novel mechanism, as hereinabove described, is accurate and effective,yet relatively easyand inexpensive to construct, assemble andmaintain inadjustment, eliminating numerous parts of the standard mechanismheretofore employed such as the regulatingand spring rails, the whip andwhip lifter, the abstract, the fly, the back check,

the catcher, etc.

While I prefer to anchor the cord 36 to the damper, this is notessential. It may, for example, be attached to rail l!) between thehammer and the strings. In such case the damper may be connected to thekey by a separate cord or maybe connected to the hammer by a second cordor by leverage so arranged that forward movement of the hammer causesretraction of the damper. Also, the co-operating groove and cliparrangement shown for attaching the hammer and damper supporting springsto the rail, while preferable, is not essential, as the springs may befastened to the rail in any suitable manner. As will be understood,therefore, these and other changes in the preferred illustratedembodiment of the invention may be made within the scope of theinvention, as set forth in the appended claims.

I claim:

1. In a striking and damping mechanism for pianos, a hammer, a hammersupport adjacent the piano strings having a groove therein, and a springmounting said hammer on said support and resiliently supporting saidhammer in spaced relation to said support in a normal position spacedfrom said strings, said spring being secured to said support byfrictional engagement of the main body thereof with the walls of saidgroove and being yieldable to permit rocking of said ham-mer intostriking engagement with oneof said strings.

2. In a striking and damping mechanism for pianos, a hammer, a hammersupport adjacent the piano strings, a spring mounting said hammer onsaid support and resiliently supporting said hammer in spaced relationto said support in a normal position spaced from said strings, saidspring being yieldable to permit rocking of said hammer into strikingengagement with one of said strings, and means incapable of resistinglongitudinally applied compressional forces operatively connecting oneof the'keys of the piano keyboard to said hammer and operative ondepression of said key to rock said hammer against the resistance ofsaid spring into striking engagement with one of said strings whileleaving the hammer free to rebound away from said stringunder-thepressure of said spring.

3. In a striking and damping mechanism for pianos, a hammer, a hammersupport adjacent the piano strings, means mounting said hammer on saidsupport for rocking to and from a position of striking engagement withone of said string-s, said mounting means including a spring yieldablyresisting rocking of said hammer toward said striking position, and acord connected to one of the keys of the piano keyboard and associatedwith said hammer, said cord arranged to be tensioned against a portionof said hammer by depression of said key to cause said hammer to rock tosaid striking position while leaving said hammer free to rebound fromsaid string under the pressure of said spring.

4. In a striking and damping mechanism for pianos, adamper, a dampersupport adjacent the piano string-s having a groove therein, a springmounting said damper on said support and resiliently supporting saiddamper in spaced relation to said support in a normal position ofdamping engagement with one of said strings, said spring being securedto said support by frictional engagement of the main body thereof withthe walls of said groove and being yieldable to permit rocking of saiddamper away from said string.

5. In a striking and damping mechanism for pianos, a damper, a dampersupport adjacent the piano strings, means mounting said damper on saidsupport .for rocking to and from a position of damping engagement withoneof said strings, saidmounting means including a spring yieldablyresisting rocking of said damper away from said position, and meansincapable of resisting longitudinally applied compressional'forcesdirectly connected to one of the keys of the piano keyboard andto said damper, said means arranged to be tensioned by depression ofsaid key to rock said damper away from said damping position.

6. In a striking and damping mechanism for pianos, a hammer having abase and striking tip, a hammer supporting rail adjacent the pianostrings, a groove in said rail having a restricted throat, and a springclip having a curved body portion fitted in said groove and frictionallyengaging the Wall thereof, said clip having an end portion protrudingthrough said throat and secured to said base of said hammer to yieldablysupport said hammer ina normal position with said tip spaced from saidstrings.

7. In a striking and damping mechanism for pianos, a damper having abase and. damping tip, a damper supporting rail adjacent the pianostrings, a groove in said rail having a restricted throat, and a springclip having a curved body portion fitted in said groove and frictionallyengaging the walls thereof, said clip having an end portion protrudingthrough said throat and secured to said .base of said damper toyieldably support said damper in a normal position with said 'tip indamping engagement with one of said strings.

8. A striking and damping mechanism for pianos which includes a hammer,a damper, means mounting said hammer and damper adjacent the pianostrings for rocking to and from respective positions of striking anddamping en gagement with one of said strings, said mounting meansincluding a spring yieldably resisting rocking of said hammer towardstriking position and a spring yieldably resisting rocking of saiddamper away from damping position, and a cord connected to one of thekeys of the piano keyboard and to said damper and associated with saidhammer, said cord arranged to be tensioned by depression of said key torock said damper away from said damping position and then to rock saidhammer into striking engagement with one of said strings while leavingsaid hammer free to rebound from said string under the pressure of saidfirst named spring.

9. A striking and damping mechanism for pianos which includes a hammer,a damper, a supporting rail for said hammer and damper adjacent thepiano strings, a first spring mounting said hammer on said rail andresiliently supporting said hammer in spaced relation to said rail in anormal position spaced from said strings, said spring being yieldable topermit rocking of said hammer into striking engagement with one of saidstrings, a second spring mounting said damper on said rail andresiliently supporting said damper in spaced relation to said rail in anormal position of damping engagement with said one of said strings,said second spring being yieldable to permit rocking of said damper awayfrom said position, and means incapable of resisting longitudinallyapplied compressional forces operatively connecting one of the keys ofthe piano keyboard to said hammer and said damper and operative ondepression of said key to rock said damper out of said damping positionagainst the resistance of said second spring and then to rock saidhammer again-st the resistance of said first spring into strikingengagement with said one of said strings while leaving the hammer freeto rebound away from said string under the pressure of said firstspring.

10. A mechanism as claimed in claim 9 where- 8 in said means is directlyattached to said key and said damper and extends about a curved surfaceof said hammer on the side of said first spring away from said strings.

11. A mechanism as claimed in claim 9 Wherein said rail is provided witha pair of grooves each having a restricted throat and said springs areeach in the form of clips each having a curved body portion seated inone of said grooves and frictionally engaging the wall thereof, saidclips each having an end portion protruding through said throat, saidprotruding end portion of one of said clips being attached to saidhammer and said protruding end portion of the other said clip beingattached to said damper.

HANS GUNN AR LINDEROTH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 316,062 Reissner Apr. 21, 1885364,399 Dopp June 7, 1887 1,063,311 Abendschien June 3, 1913 1,167,863West Jan. 11, 1916 1,176,655 Cross Mar. 21, 1916 1,563,526 Purrer Dec.1, 1925 2,146,114 Finholm Feb. 7, 1939 2,227,741 Betz Jan. 7, 1941FOREIGN PATENTS Number Country Date 736 Great Britain Feb. 19, 1880

